A portal of entry<span> is the site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various </span>portals<span>, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.</span>
<span>The Hadley, Ferrel, and polar cells are all patterns of atmospheric circulation. </span>
The answer would be bone marrow
The answer from my knowledge would be B.
